In a newborn's mouth, what type of bacteria is expected to be present during the first few hours?

In a newborn's mouth, the expectation of bacterial presence during the first few hours aligns with the concept that they are born relatively sterile, with their mouths gradually colonized by various microorganisms after birth.

The time immediately after birth is characterized by a lack of significant microbial colonization. As the newborn is exposed to their environment, including the mother and other caregivers, they begin to acquire bacterial colonization. This initial period is crucial for establishing a healthy oral microbiome.

Commensal bacteria, which are the non-pathogenic bacteria that inhabit our bodies, will soon begin to populate the mouth; however, they typically do not establish themselves immediately at birth. Aerobic and pathogenic bacteria are also not expected to be present in significant numbers within the first hours. Thus, this gradual introduction of bacteria marks the transition from an almost sterile mouth to one that supports the diverse community of microbes typical of oral health.